Fire alarm apparatus



lJune 24 1941. y, C, CID

' FIRE ALARM APPARATUS Fied June 19, 1959 6246074 C22? By AJ Attorneys Patented June 24,l 941 UNITED STAT Es l PATENT oFFicE r' ammi ma ArPARATUs Jamil C. Cid, Montreal, Quebec, Canada Application Junelil, 1939, Serial No. 279,889 z'oiaims. fm1. zoo-14o) ratus is subjected to temperature above a predetermined degree.

A further object of the invention is'the provision of fire-alarm apparatus wherein the signal will become operative if the primary electric cir- I cuit becomes dead or broken.

Still anotherV object of the invention is the provision offilre-al'arm apparatus of the aforesaid character which is efficient and reliable in joperation.

A stm further' object of the invention is the I' provision of lire-alarm apparatus of the above character which is relatively simple in construction.

Other objects and advantages of the invention will become apparent as the description progresses.

In the accompanying drawing forming a part of this specification and in which like reference "characters are employed to designate corresponding parts throughout the same:

Figure 1 is aperspective view of the apparatus installed on the ceiling of a chamber,

to form a gap therebetween. To lthe outer por outer ends attached to supporting brackets Il and their inner ends disposed in spaced relation tions of the arms I'I are secured, by screws i8, the end portions of an upstanding approximately U-shaped metallic frame 20 provided with an7 internal threaded aperture in thecentre of the cross bar 2i adapted to receive therethrough a vertically arranged adjustable contact screwj! formed with an enlarged knurled head 23 and secured in adjusted position by a lock-nut 24.

` To the inner adjacent end portions of the arms i1 are securedapair of complementary angular contact elements, 2l fastened by terminal screws 2l. and forming parallel contact wings 2l. One

of the screws 21 is connected, through a conduc tor 29, with a transformer 3l while the comple` mentary screw 21 connects, through the medium of a conductor 3i, with an electro-magnet l2 which in turn connects with the transformer I. through a conductor il; The transformer also makes `connection with conventional feed wires 34 which connect with a conventional outlet or other soirce of electrical current. The electromagnet I2 is adapted to actuate a switch arm ll which may be pivoted at one end. as indicated at 38 connected to the arm 35 normally tends to 'Figure 2 is a sectional view therethrough showing the signal circuit open,

Figure 3 is a similar view showing thesignal circuit closed, and

Figure 4 is an enlarged sectional view taken on the line 4--4 of Figure 3.

Referring to the drawing, wherein vor the purpose of illustration is shown a preferred embodiment of the invention, i/,designates a casing, in

ll, and which carries at its outer free end a contact 31 and an armature 3l. A tension spring swing the arm so that the contact 31 is held against a. fixed switch contact IB and is yieldable to allow the outer end of the arm to move away from the fixed contact 4I and against the electromagnet when theLlatter is energized.

thev present example embodying a hollow cylindrical member which may be formed of -sheet metal vor the like having an. enlarged annular part ,il at the inneropen end. At the outer closed ena th casing is provided wann plurality of vent apertures i2. When, as in the present illustration, the apparatus is mounted in association. with a 'ceiling connection, the annular flange of the end enlargement il is attached by screws I3 to iianged fitting Il fastened to the ceiling support by screws Il with the main cylindrical chamber I l depending from the ceiling.v

At the intermediateportion of the casing body il are provided a pair of transversely extending aligned complementary arms i1 having their A conductor wire I2 connects the pivoted end u of the switch arm :s with the terminal connecl tion 43 on the casing. A branch wire 44 connects the switch arm pivot connection with the conductor 3i. The fixed switch contact 4l is connected with a signal 4l, in the present instance a conventlonal electric bell, through-the medium of a conductor 48 Awhilethe opposite terminal ofthe bell vconnects with a battery 41 through a wire ll.

The battery 41 connects with a terminal screw 4l on the frame 2l through the medium of a conductor wire 5 0 which is also joined to the conductor 29.

In the lower -portion of the casing body il is mounted a thermostat 5 2, in thepresent example in the form of a bellows type thermostatic element expansible longitudinally of the casing.

At the outer end, the thermostat 62 is formed with an axially disposed boss 53 iltted in a socket v Il at the end of the main. casing chamber. At

the opposite inner end an elongated stem 'Il of signal B5 in the battery circuit. Thus, the A ble signalsounds the nre alarm.

conducting material is secured in amai position to the thermostat and extends in-a line through the gap between the arm il and the contact wing 20. Upon the stem E is secured a sleeve 58,'of non-conducting material, removably held in position by a screw 51 engaging an interiorly threaded bore E8 in the outer end of the stem and having an enlarged head 59 bearing against the end amasar In the event that disconnected or should become dead for any o! the sleeve to tightly hold the same on the stem. t

The end portion of the sleeve 55 isexteriorly lthreaded to receive a contact element @@:which may be in the form of a non-circular nut formed of conducting material.

Under. normal conditions, .the primary circuit through the transformer and electro-magnet is closed, inasmuch as the. electro-magnet is enerreason,- while-the apparatus is in its normal in? operative position, the electro-magnet being deenergized will cause closure of the secondary circuit by release of the contact 3l which, at such time, engages the fixed contact ill and causes the battery and signal circuit through the branch wire St' andthe connection oi-the wires 39 i, to signal the defective state of the apparatus. x It is -tobe, understood that the form of my invention herein', shown and described is to bel "taken as a preferred example of the same, and

gized to eiect a circuit through the conductors l33, vt and 2S and through the spaced switch contacts 26 by the nut t@ which bridges these contact elements.

-.Whe'n the thermostatic element 52 is exposed vor subjected to a temperature exceeding a predetermined degree, as for example a temperature -of 130 F. as would be caused-by a fire inthe vicinity of the apparatus, the thermostat expands from the form shown at Figure 2 to that shown at Figure 3, with the result that the stem on the inner end thereof -is moved axially. In consequence o such movement, the contact nut 6@ ls .carried to an upward position disengaging the wings 2@ and the head oi the screw 5l isforced against and contacts with the screw 22. This action brakes the primary circuit through the electro-magnet so that the movable switch con-' tact Si is swung, through the medium of the spring 39,.4 against the hxed contact d0, while. the

secondary circuit is completed through the conductor 42, the casing, the thermostat, the stem 5 5. the screw 5l, the spring 22, the frame bar t, andthe conductors BS, t8 and 50 to energize the that various changes as to the shape. size and element and adapted to follow the movements thereof, a pair of wide spaced contacts disposed symmetrically with respect to the stem, means on said stem for shorting the contacts during the `ilrst expansion stage of the element, andan auxiliary contact above the spaced contacts .and adapted to engage the endv of the stem after saidn last shorting means'havemovedout of engage ment with the spaced contacts. i

2. In aswitch of the/character described,

vented casing, van exliansible .thermostatlc element in said casing, a stem on said element.

adapted to follow the expansion movement of. the element, a pair of parallel contacts, means Ion thestem for Isnorting said` contacts during thev initial movement ofthe stem,and an auxiliary contact above the parallelfcontacts adapted to. engage the stem after the snorting means there;- .of have disengaged the parallel contacts.

the feed conductors 343 arev 

